Shortening code using functions - c++

Question

I'm new to coding and i have a question about how to shorten code using function. My homework problem says that i need to take out the nested loops and shorten my previous code using functions and i need a little help jump starting. This code displays 100 random hex colors. I apologize for the messy code, still learning.
#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
int main(){
srand(time(0));
for(int j=0; j<100; j++){
for(int i=0; i<6; i++){
int digit = rand() % 16;
char letter;
if(digit > 9){
letter = digit + 55;
cout << letter;
}
else{
cout << digit;
}
}
cout << endl;
}
return 0;
}

Answer 1

Your problem statement suggests you modify the code as follows, but note that this does not reduce code size, just makes it more readable:
#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
void innerLoop(){
char letter;
int digit;
for (int i = 0; i<6; i++){
digit = rand() % 16;
if (digit > 9){
letter = digit + 55;
cout << letter;
}
else{
cout << digit;
}
}
}
int main(){
srand(time(0));
for (int j = 0; j<100; j++){
innerLoop();
cout << endl;
}
return 0;
}

Answer 2

As an alternative to code frenzy' code change, there's an easier solution (although not necessarily educative) - generating 1000 decimal integers, then converting them to hexadecimal when printing using std::hex.
#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
int main(){
srand(time(0));
for(int j=0; j<100; j++){
int number = rand() % 1000; // Or whatever your upper limit is.
cout << hex << number << endl;
}
cout << endl;
return 0;
}

Answer 3

The innermost loop is generating a random hexadecimal digit and printing that.
Let's break out the generation of digits into a function:
char random_digit() {
int digit = rand() % 16;
if (digit > 9) {
return digit - 10 + 'A';
}
else {
return digit;
}
}
int main() {
srand(time(0));
for(int j = 0; j < 100; j++) {
for(int i = 0; i < 6; i++){
cout << random_digit();
}
cout << endl;
}
}
Now we have a loop that prints a number of random digits.
We can turn that into a function too.
Let's give it a parameter so we don't need to hard-code the length:
void print_number(int length) {
for (int i= 0; i < length; i++) {
cout << random_digit();
}
cout << endl;
}
// New main
int main() {
srand(time(0));
for(int j = 0; j < 100; j++) {
print_number(6);
}
return 0;
}